4d.  E.  S.  Library.  C©P.  Sl  -^ 

CONNECTICUT  •  '^  ^"^ 

AGRICULTURAL  EXPERIMEIT  SIATIOH 

NE\V    HAVEN,    CONN. 


BULLETIN   153,  MARCH,  1906. 


ENTOMOLOGICAL    SERIES,    No.    13. 

The  Gypsy  Moth  and  the  Brown-Tail  Moth. 


FEMALE    GYPSY    MOTH. 
(After  Howard,  Bur.  of  Ent.,  U.  S.  Dept.  of  Agr.) 

CONTENTS. 

Page. 

The  Gypsy  Moth  and  the  Brown-Tail  Moth  3 

Connecticut  invaded  by  the  Gypsy  Moth 3 

The  Gypsy  Moth 4 

Life  history  and  injury 4 

Means  of  distribution   6 

Natural  enemies 7 

Importation  of  parasites 7 

Remedial  measures   7 

The  Brown-tail  Moth 8 

Habits  and  life  history 8 

Means  of  control  10 


The  Bulletins  of  this  Station  are  mailed  free  to  citizens  of  Con- 
necticut -who  apply  for  them,  and  to  others  as  far  as  the  editions 
permit. 


CONNECTICDT  ASRICDLTURAL  EXPERIMENT  STATION, 

BOARD   OF   CONTROL. 
His  Excellency,  Henry  Roberts^  Ex  officio.  President. 

Prof.  F.  G.  Benedict  Middletown. 

Prof.  W.  H.  Brewer,  Secretary New  Haven. 

B.  W.  Collins  Meriden. 

T.  S.  Gold West  Cornwall. 

Edwin  Hoyt  New  Canaan. 

J.  H.  Webb Hamden. 

E.  H.  JenkinSj  Director  and  Treasurer New  Haven. 


STATION   STAFF. 

Chemists. 

Analytical  Laboratory. 

A.  L.  WiNTON,  Ph.D.,  Chemist  in  charge. 

E.  Monroe  Bailey,  M.S.  •      J.  L.  Kreider,  M.A. 

Kate  G.  Barber,  B.S.  E.  J.  Shanley,  Ph.B. 

Laboratory  for  the  Study  of  Proteids. 
T.  B.  Osborne,  Ph.D.,  Chemist  in  charge.  I.  F.  Harris,  M.S. 

Botanist. 
G.  p.  Clinton,  S.D. 

Entomologist. 
W.  E.  Britton,  Ph.D. 

Assistant  to  the  Entomologist. 
B.  H.  Walden,  B.Agr. 

Forester. 
Austin  F.  Hawes,  M.F. 

Agronomist. 
Edward  M.  East,  M.S. 

Grass  Gardener. 
James  B.  Olcott,  South  Manchester. 

Stenographers  and  Clerks. 

Miss  V.  E.  Cole. 

Miss  L.  M.  Brautlecht. 

Miss  E.  B.  Whittlesey. 

In  charge  of  Buildings  and  Grounds. 

William  Veitch. 

Laboratory  Helper. 
Hugo  Lange, 

Sampling  Agent. 
V.  L.  Churchill,  New  Haven. 


The  Gypsy  Moth  and  the  Brown-Tail  Moth. 


BY 


W.    E.    BRITTON, 

State  Entomologist. 


Connecticut  Invaded  by  the  Gypsy  Moth. 

The  gypsy  moth  is  already  in  Connecticut,  specimens  having  been 
found  at  Stonington,  and  the  entomologist  is  now  hunting  and  destroy- 
ing the  egg-masses.  Everything  will  be  done  to  exterminate  the  pest 
in  this  locality. 

THE  DANGER  TO  CONNECTICUT. 

There  is  good  reason  to  fear  that  both  of  these  pests  will  soon  bring 
havoc  to  the  vroodlands  of  the  state.  The  gypsy  moth  attacks  all 
kinds  of  trees  including  pines  and  other  cone-bearing  trees,  wrhich  are 
ruined  by  defoliation  much  sooner  than  deciduous  trees.  Fruit  and 
shade  trees  suffer  alike. 

The  brov7n-tail  moth  attacks  fruit  trees  and  some  of  the  woodland 
trees,  devouring  the  leaves ;  it  is  also  a  great  nuisance,  as  the  larval 
hairs  break  off,  and  on  coming  in  contact  with  the  human  skin,  cause 
extreme  irritation  and  sometimes  illness. 

WHAT  TO  DO. 

It  is  earnestly  requested  that  any  suspected  specimens  of  eggs, 
caterpillars  or  adults  be  called  to  the  attention  of  the  State  Entomol- 
ogist of  this  station  in  order  that  he  may  identify  them.  He  Avill  co- 
operate, so  far  as  he  is  able,  in  checking  and  exterminating  these 
dangerous  and  destructive  enemies  of  all  trees  and  shrubs.  Directions 
for  combating  these  insects  will  be  found  in  the  following  pages. 

TRANSPORT  NO  LIVING  INSECTS. 

It  is  against  the  United  States  laws  to  send  living  insects  by  mail, 
and  violations  of  the  law  are  punishable  by  a  heavy  fine  and  imprison- 
ment. It  would  be  dangerous  to  send  such  pests  as  the  gypsy  or 
brown-tail  moths  in  any  stage  of  their  existence,  if  alive.  All  insect 
specimens  should  therefore  be  killed  before  sending  them  to  be  identi- 
fied. 


4  CONNECTICUT    EXPERIMENT    STATION    BULLETIN    I53. 

Eggs,  pupae  and  larvae  can  be  killed  by  dropping  them  into  a  jar  of 
alcohol,  benzine  or  gasoline  and  leaving  them  for  a  few  hours.  When 
removed  the  liquid  evaporates  and  they  are  in  good  shape  for  identifica- 
tion. Beetles,  bugs  and  scale  insects  can  be  treated  in  the  same  vray. 
Moths  and  butterflies  may  be  killed  by  the  fumes  of  cyanide,  chloroform, 
ether,  carbon  bisulphide,  or  they  may  be  submerged  in  gasoline  or  ben- 
zine, which  kills  them  quickly  without  injuring  them  for  the  purpose  of 
identification.  They  should  be  packed  in  a  tin,  wood  or  strong  paste- 
board box  which  will  not  be  crushed  in  transit. 


THE  GYPSY   MOTH. 
Porthetria  dispar  Linn. 

An  outbreak  of  the  gypsy  moth  in  Eastern  Massachusetts 
was  met  by  an  appropriation  by  the  Legislature  of  that  state 
for  the  purpose  of  suppressing  the  insect.  Exterminative 
work  was  commenced  in  1890  and  kept  up  for  ten  years,  when 
it  was  discontinued.  During  this  period  over  $1,000,000  was 
expended  and  the  insect  was  so  far  checked  that  it  was  doing 
little  damage  in  1900.  In  1905  the  pest  had  spread  over  so 
much  territory  and  had  become  so  troublesome  that  the  com- 
monwealth again  took  the  matter  in  hand,  and  is  endeavoring 
to  control  the  insect  under  the  superintendence  of  Mr.  A.  H. 
Kirkland,  an  appropriation  of  $300,000  being  available  to  carry 
on  the  work  until  May,  1907. 

At  the  present  time  the  insect  is  found  throughout  the 
eastern  portion  of  Massachusetts,  southeastern  New  Hamp- 
shire, and  a  region  in  and  about  Providence,  R.  L,  is  known 
to  have  been  infested  for  two  years  or  more.  It  has  been 
reported  several  times  in  Connecticut,  but  always  proved  to  be 
some  other  species.  In  July,  1905,  two  adult  female  moths 
were  taken  and  two  males  were  seen  by  Mr.  E.  Frensch  at 
Stonington,  and  recently  egg-masses  have  been  found  in  the 
same  locality. 

Life  History  and  Injury. 

The  eggs  are  laid,  usually  on  the  trunks  and  branches  of 
trees,  in  July  and  August,  in  oval  masses  each  containing 
about  500  eggs  and  covered  with  hair  as  shown  in  Figure  i. 

The  eggs  hatch  about  May   ist,  and  the  young  caterpillars 


THE    GYPSY    MOTH. 


5 


soon  begin  to  feed  upon  the  expanding  foliage,  devouring  all 
kinds  of  vegetation,  even  defoliating  coniferous  trees.  All 
the  damage  is  done  in  this  stage.  As  the  caterpillars  approach 
maturity,  they  feed  mostly  at  night,  and  seek  shelter  during 
the  day  on  the  shady  side  of  the  trunks,  under  fence  rails, 
stones  and  rubbish,  where  they  may  often  be  found  in  large 
numbers. 

When  full-grown,  the  caterpillar  is  between  two  and  three 
inches  long,  dark  brown,  with  two  rows  of  red  spots  and  two 


Fig.  I. — Egg-mass  of  gypsy  moth. 

(After  Kirkland.) 


rows  of  blue  spots  along  the  back,  and  is  covered  with  long 
hairs.  (See  Figure  2.)  The  caterpillar  usually  reaches  full  size 
in  July,  and  transforms  to  a  pupa  or  chrysalis,  usually  spinning 
a  few  threads  about  itself,  as  is  shown  in  Figure  3. 

During  the  latter  half  of  July  the  adult  moths  emerge,  mate, 
and  the  females  lay  eggs.  The  brown  male  has  a  wing  expanse 
of  one  and  one-half  inches,  and  flies  about  in  the  daytime  in 
a  zigzag  course.  The  female  has  a  heavy  body,  and  does  not 
fly  far,  though  furnished  with  wings  which  expand  about  two 
inches,  and  which  are  nearly  white,  with  delicate  black  mark- 
ings. See  front  page  of  this  bulletin.  The  male  is  shown  in 
Figure  4.     There  is  but  one  brood  each  season. 


6  CONNECTICUT    EXPERIMENT    STATION    BULLETIN    1 53. 

Means  of  Distribution. 

As  the   caterpillars   of  both  species   crawl   about  in   going 
from  one  tree  to  another,  they  are  very  apt  to  invade  freight 


Fig.  2. — Gypsy  moth  caterpillar. 

(After  Howard,  Bur.  of  Ent., 
U.  S.  Dept.  of  Agr.) 


Fig.  3. — Cocoon  of  gypsy  moth. 

(After  Howard,  Bur.  of  Ent,, 
U,  S.  Dept.  of  Agr.)    • 


cars  on  the  siding,  and  be  carried  to  other  places.     Both  kinds 
of   caterpillars   have   the   habit   of   spinning   down   on   slender 


Fig.  4. — Male  gypsy  moth. 
(After  Howard,  Bur.  of  Ent.,  U.  S.  Dept.  of  Agr.) 

threads  from  their  food  trees,  and  may  thus  drop  on  carriages, 
automobiles  or  railroad  cars,  and  be  carried  long  distances 
into  a  part  of  the  country  heretofore  uninfested. 


THE    GYPSY    MOTH. 


Natural  Enemies. 


There  are  several  species  of  parasitic  Hymenoptera,  Diptera 
and  predaceous  insects  that  attack  both  the  gypsy  and  brown- 
tail  moths  in  Massachusetts,  and  they  are  also  devoured  by  birds, 
toads,  and  other  insectivorous  animals.  But  all  of  these  work- 
ing together  do  not  control  the  pests. 

Importation  of  Parasites. 

In  Europe,  the  native  home  of  these  insects,  there  are  a 
larger  number  of  parasitic  enemies  belonging  to  species  not 
found  in  this  country.  During  1905,  Dr.  L.  O.  Howard,  the 
Government  Entomologist,  in  cooperation  with  the  Massachu- 
setts authorities,  collected  in  Europe  some  of  the  parasites 
of  the  gypsy  and  brown-tail  moths,  and  sent  them  to 
Massachusetts,  where  they  will  be  reared  and  finally  distributed 
in  the  infested  region.  Of  course  these  parasites  may  not  be 
able  to  thrive,  or  even  to  live,  in  this  country,  but  it  is  an 
experiment  worth  trying,  and  we  certainly  hope  for  much 
benefit  from  it. 

Remedial  Measures. 

One  of  the  most  effective  means  of  controlling  the  gypsy 
moth  is  by  destroying  the  egg-masses  on  the  trunks  and 
branches  of  trees,  on  fences,  stones,  or  wherever  they  occur. 
A  sponge,  brush  or  swab  is  dipped  in  creosote  mixture,  and 
the  egg-masses  are  saturated  with  it.  A  long  pole  can  be 
used  to  reach  the  egg-masses,  but  it  is  often  necessary  for 
men  to  climb  about  in  the  trees  in  order  to  reach  them.  Where 
brush  land  is  badly  infested,  it  is  often  best  to  cut  and  burn 
the  brush  between  August  and  May  to  destroy  the  eggs. 
Spraying  the  foliage  with  arsenate  of  lead,  using  5  pounds  to 
50  gallons  of  water,  will  of  course  save  the  trees  from  injury 
for  the  season.  This  poison  adheres  to  the  tree  for  a  long 
time,  and  will  not  injure  the  leaves.  Paris  green  can  be  used 
at  the  rate  of  one  pound  in  100  gallons  of  water,  but  two 
pounds  of  lime  should  be  added  to  prevent  injury  to  the 
foliage.  This  mixture  will  not  adhere  to  the  leaves  as  well 
as  arsenate  of  lead. 


8  CONNECTICUT   EXPERIMENT    STATION    BULLETIN    1 53. 

The  caterpillars  can  be  gathered  and  destroyed  while  rest- 
ing on  the  tree  trunks  or  hiding  under  rubbish  during  the  day. 
The  chrysalids  or  pupae  will  be  found  in  similar  places,  and  can 
also  be  destroyed  by  heat  or  by  crushing. 


THE    BROWN-TAIL    MOTH. 

Euproctis  chrysorrhaea  Linn. 

This  insect  was  first  noticed  in  Somerville,  Mass.  in  the 
early  nineties,  but  was  supposed  to  be  some  native  species. 
It  increased  in  abundance,  and  was  brought  to  the  attention  of 
entomologists  in  1897,  who  found  it  to  be  the  brown-tail  moth, 
a  European  pest  introduced  probably  by  accident  into  this 
country.  A  special  appropriation  was  granted  by  the  Legisla- 
ture for  fighting  this  insect,  and  the  matter  was  placed  in 
charge  of  the  Gypsy  Moth  Commission,  but  all  work  of  the 
Commission  was  discontinued  in  1900.  The  brown-tail  moth 
has  spread  rapidly  to  the  north  through  Southeastern  New 
Hampshire,  Maine,  and  adults  have  been  captured  in  St.  John, 
New  Brunswick,  but  may  have  been  carried  there  by  boats 
from  Boston.  The  spread  southward  has  been  less  rapid, 
Cape  Cod  being  the  most  southerly  point  known  to  be  infested. 
Toward  the  west  the  insect  has  reached  Amherst,  Mass. 

Habits    and    Life   History. 

The  eggs  are  laid  in  masses  of  about  300,  on  the  under  side 
of  the  leaves,  the  egg-masses  being  smaller  and  more  elongated 
than  those  of  the  gypsy  moth.  They  are  also  more  of  a  red- 
dish color,  but  are  covered  with  hair  in  much  the  same  manner. 
Egg-laying  takes  place  between  the  middle  and  the  end  of 
July. 

The  eggs  hatch  early  in  August,  and  the  young  caterpil- 
lars feed  gregariously  upon  the  upper  leaf  surface,  but  soon 
begin  to  fasten  a  number  of  leaves  together  with  silken  threads 
which  they  spin,  forming  a  nest  or  web  on  the  ends  of  the 
small  branches.  On  the  approach  of  cold  weather,  about  250 
caterpillars  enter  each  web,  and  remain  there,  about  one- 
fourth  grown,  through  the  winter,  coming  out  early  in  April 
and   feeding  upon  the  buds,   and  later  the  opening  blossoms 


THE   BROWN-TAIL    MOTH. 


and  leaves.  The  caterpillars  feed  during  the  day,  and  attack 
a  large  number  of  plants,  preferring  pear,  cherry,  apple  and 
other   fruit  trees,   but  also  attacking   shade   and   forest   trees, 


Fig.  5. — Caterpillar  of  brown-tail 

moth. 

After  Fernald.) 


Fig.  6. — Web  or  winter  nest  of 

brown-tail  moth. 

(After  Fernald.) 


especially  the  oak.     Large  trees  are  often   stripped  of  their 
leaves. 

When    full-grown,    the    caterpillars    are    about    two    inches 


Fig.  7. — Female  brown-tail  moth. 

(After  Fernald.) 


long,  dark  brown  with  an  interrupted  white  stripe  on  each  side, 
and  two  conspicuous  red  dots  on  the  back.     They  are  covered 


lO         CONNECTICUT    EXPERIMENT    STATION    BULLETIN    1 53.   ■ 

with  long  hairs  which  are  finely  barbed  and  brittle.  These 
break  off,  and,  on  coming  in  contact  with  the  human  skin, 
cause  great  irritation  and  sometimes  serious  illness.  The  full- 
grown  caterpillar  is  represented  by  Figure  5,  and  Figure  6 
shows  the  appearance  of  the  web  or  winter  nest. 

The  caterpillars  become  full-grown  the  last  of  June,  make 
their  cocoons  at  the  tips  of  the  twigs,  often  in  a  bunch  of 
leaves,  and  the  moths  emerge  two  weeks  later,  or  about  the 
middle  of  July. 

The  moths  are  pure  white  except  the  end  of  the  abdomen, 
which  is  brown,  giving  it  the  name  of  brown-tail  moth.     The 


Fig.  8. — Tree  pruner. 

female  has  a  wing  spread  of  about  one  and  one-half  inches, 
while  the  male  is  somewhat  smaller.  (See  Figure  7.)  Both 
sexes  fly  at  night,  and  may  be  taken  around  electric  lights. 

Means   of   Control. 

The  best  of  all  remedies  against  this  insect  is  the  destruc- 
tion of  the  caterpillars  in  the  winter  webs  or  nests.  The  winter 
nests  can  be  readily  seen  on  the  twigs  throughout  the  winter,, 
and  these  should  be  clipped  off  with  a  long-handled  tree 
pruner  such  as  is  shown  in  Figure  8,  and  gathered  and  burned. 
The  caterpillars  are  hibernating  in  these  nests  from  October 
to  April.     It  is  of  no  use  to  cut  off  the  nests  and  leave  them 


THE    BROWN-TAIL    MOTH.  II 

on  the  ground,  as  the  caterpillars  may  remain  uninjured. 
All  should  be  gathered  and  burned. 

Spraying  with  poison,  as  has  been  described  for  the  gypsy 
moth,  can  be  practiced ;  the  brown-tail  caterpillars  are  more 
susceptible  to  the  effect  of  poisons  than  the  gypsy  caterpillars. 

Caterpillars  which  are  crawling  about  in  great  numbers  on 
trees,  fences,  etc.,  should  of  course  be  destroyed.  Sprinkling 
with  kerosene,  either  pure  or  in  an  emulsion,  or  even  with 
strong  soapsuds,  is  of  considerable  value  in  destroying  them. 


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